The inventions of this application were the subject of Disclosure Documents Nos. 129,280 and 129,281 filed in the U.S. Patent and Trademark Office on July 20, 1984.
Most of the world, and particularly developing countries, suffer from an inadequate supply of energy resources. There has, as a result, been substantial efforts toward building engines which can efficiently utilize those energy resources which are locally available. Such energy sources include wood, rice husks or other vegetative or animal waste products. A leading engine showing great promise is the Stirling engine which is capable of converting heat energy directly to mechanical energy.
Cost and durability are very important in such applications of Stirling engines. They must be sufficiently inexpensive that they are affordable for those who need them and must provide reliable operation without the need for frequent repair because they are often used in locations which are inaccessible to adequate repair facilities.
Particularly vulnerable in a crank-type Stirling engine are the linkages which drivingly connect the power output shaft of the Stirling engine to its displacer and power piston. In order to provide such linkages, which give a reasonable and acceptable life expectancy, the bearings in those linkages must be made large using conventional designs. If the loading forces on the displacer drive linkages are reduced, the bearings of those linkages may be made correspondingly smaller and will exhibit a longer lifetime.
It is therefore a purpose and object of the present invention to provide a means for reducing the loading forces in the displacer drive linkages without changing the operating characteristics of the engine. This results in longer lasting, smaller and less expensive bearings and linkages.
It is often desirable to construct a Stirling engine which is intended for the operation described above so that it utilizes normal atmospheric air as its working gas. Since such Stirling engines operate more efficiently with working gas at a higher mean pressure than atmospheric pressure, there have been a variety of designs suggested for pumps which may be driven by the crank shaft of the engine. With such a pump, the engine may be started with working gas at atmospheric pressure and is able to do enough work to pump itself up to operating pressure. However, pumps designed in the past for this purpose add substantial material and labor costs and complexity to the engine and thus unduly increase the sales price.
It is therefore a further purpose and object of the present invention to provide a self pumping mechanism requiring a minimum of additional structure within the engine.